DE102017215334A1 - Method, computer program product and measuring system for operating at least one triangulation laser scanner for identifying surface properties of a workpiece to be measured - Google Patents

Abstract

The invention relates to a method 40, a computer program product and a measuring system 18 for operating at least one triangulation laser scanner 1 for identifying surface properties of a workpiece 7 to be measured by means of the at least one triangulation laser scanner, the at least one triangulation laser scanner 1 comprising a CMOS sensor chip 11 , an imaging optics 9 and a laser line light source 3 for generating a laser line on the workpiece to be measured 7 under a Scheimpflug condition, wherein the data generated on the CMOS sensor chip 11 in an image recording data is reduced to an amount of data which only the data of Lateral actual position of the pixels of the laser line and the data comprises at least one quality criterion for each of the pixels of the laser line, wherein the quality criterion is a measure of the intensity distribution along a direction transverse to the local extension direction of the pixels Laser line on the CMOS sensor chip and wherein the reduced amount of data with respect to the quality criterion by means of at least one evaluation unit 30 with respect to the presence of bar and / or recognition code information 13 and / or texture information 15 is analyzed.

Description

The invention relates to a method, a computer program product and a measuring system for operating a triangulation laser scanner for identifying surface properties of a workpiece to be measured, wherein the triangulation laser scanner has at least one CMOS sensor chip.

Triangulation laser scanners for detecting surface coordinates of a workpiece to be measured are well known from the prior art. The newer triangulation laser scanners use a CMOS sensor chip, which enables the capture of image files in so-called HDR formats. In the case of the triangulation laser scanners, the lateral deviation of the image position of a laser line from its nominal position on the sensor chip is related to the distance of the triangulation laser scanner to the surface of the workpiece to be measured by means of classical triangulation in order to evaluate the surface coordinates of a workpiece to be measured. With triangulation laser scanners, only the lateral X and Y positions of a bright pixel on the sensor chip are therefore important. Particularly in the case of triangulation laser scanners with a Scheimpflug arrangement of the laser light plane, the objective plane of the imaging system and the receiver plane of the CMOS sensor chip to one another, only those surface points of the workpiece to be measured are sharply imaged onto the CMOS sensor, which are located in the laser light plane. All other surface points of the workpiece to be measured are not displayed at all. Thus, with triangulation laser scanners with a Scheimpflug arrangement, only those X and Y positions can be detected as two-dimensional data on the sensor chip which correspond to an intersection of the laser light plane with a surface point of the workpiece.

In addition to such triangulation laser scanners, all possible forms of bar code scanners, ranging from the bar code reading pen to the camera or mobile phone scanner known from the prior art. Furthermore, it is off US 6,260,001 B1 known to use a barcode scanner for volume measurement. Simple barcode readers can only read one-dimensional barcodes, while camera or mobile scanners can even read two-dimensional barcodes. For this purpose, obtained pixel information or image files of the readers are evaluated by means of known evaluation methods for bar code recognition or by known methods of image processing. In addition to the lateral X and Y position of a bright pixel, the brightness of the pixel on the sensor chip of a barcode reader is therefore also important for the evaluation of the barcode. As such, prior art bar code scoring typically relies on complete image files of the sensor chip reading all the pixels of the sensor surface of the sensor chip and can not use the typical data of a triangulation laser scanner, as will be discussed below ,

In addition to triangulation laser scanners and bar code readers, cameras, in particular color cameras, are known for texturing of surfaces in 3D coordinate metrology, see US 8,284,240 B2 , In general, the two-dimensional data of such color cameras are used to design the obtained 3D data in the visualization against the user according to the associated surface texture. The surface texture can be given here only by the color of the surface. However, it is also possible to recognize other properties of the surfaces, such as, for example, the roughness as surface texture. For this purpose, for example, smooth glass surfaces of the workpiece to be measured in the visualization compared to the user can be considered by the associated 3D data of the glass surface are displayed in the color blue. Such surface texture detection cameras, as well as bar code readers for two-dimensional bar code recognition, rely on the two-dimensional sensor chip to acquire a full two-dimensional sensor surface area data corresponding to its brightness or color information content for the presence of bar code information and / or for the presence of texture information.

Triangulation laser scanners' sensor chips, in contrast to texture recognition cameras and unlike barcode scanners, are used to acquire 3D coordinates from high-speed surfaces, enabling fast scanning of surfaces. For this a reduction of the data volume is inevitable. As a rule, only the data relating to the lateral X, Y positions of the bright pixels and a quality criterion for each of the bright pixels are transmitted to reduce the amount of data. Thus, only the coordinates of the "bright" fraction of the two-dimensional data set of the entire sensor surface are used. The quality criterion serves to mark a measured value or a measuring point for an evaluation as valid or invalid. As already mentioned, especially when using triangulation laser scanners with Scheimpflug arrangement, only such reduced data can be detected, since only the points within the Laser light plane can be sharply imaged. This reduced amount of data is far less extensive than the complete two-dimensional data set of a sensor image, which means that this reduced data set can also be transmitted at high clock rates. However, the prior art triangulation laser scanner data transmitted so far can not be evaluated by bar code evaluations and / or prior art texture evaluations for the presence of bar code information and / or for the presence of texture information since the lateral X, Y position data of the detected laser lines do not contain corresponding information.

The object of the present invention is therefore to provide a method, a computer program product and a measuring system for operating at least one triangulation laser scanner, wherein at the same time for operating the triangulation laser scanner for detecting surface coordinates, an identification of the surface of the workpiece to be measured using a barcode and / / or by a texture is possible.

• • Bereitstellen mindestens eines Triangulations-Laserscanners mit einem CMOS Sensorchip, einer Abbildungsoptik und einer Laserlinien-Lichtquelle zur Erzeugung einer Laserlinie auf dem zu vermessenden Werkstück, wobei der CMOS Sensorchip und die Laserlinien-Lichtquelle in Relation zur Abbildungsoptik unter einer Scheimpflug-Bedingung angeordnet sind;
• • Bereitstellen eines Werkstücks, dessen zu vermessende Oberfläche mindestens zwei verschiedene Bereiche mit zueinander unterschiedlicher Textur und/oder mindestens einen Barcode-Bereich aufweist;
• • Erfassen der Oberfläche des zu vermessenden Werkstücks mittels des mindestens einen Triangulations-Laserscanners durch Relativbewegung des mindestens einen Triangulations-Laserscanners zu dem zu vermessenden Werkstück oder umgekehrt, wodurch wenigstens ein Teil der Oberfläche des Werkstücks mit der Laserlinie überstrichen und hierbei die laterale Ist-Position der Bildpunkte der Laserlinie auf dem CMOS Sensorchip erfasst wird;
• • Beschränken der auf dem CMOS Sensorchip bei einer Bildaufnahme erzeugten Datenmenge auf eine reduzierte Datenmenge, welche lediglich die Daten der lateralen Ist-Position der Bildpunkte der Laserlinie und die Daten mindestens eines Qualitätskriteriums für jeden der Bildpunkte der erfassten Laserlinie umfasst, wobei das Qualitätskriterium ein Maß für die Intensitätsverteilung entlang einer Richtung quer zur lokalen Erstreckungsrichtung der Bildpunkte der Laserlinie auf dem CMOS Sensorchip ist;
• • Übertragen der reduzierten Datenmenge an mindestens eine Auswerteeinheit mit einer Taktrate, welche größer ist als die maximal mögliche Taktrate zur Auslesung aller Pixeldaten des gesamten CMOS Sensorchips;
• • Erzeugen von Oberflächenkoordinaten des zu vermessenden Werkstücks anhand der auf dem CMOS Sensorchip erfassten Bildpunkte der Laserlinie mittels der mindestens einen Auswerteeinheit, wobei die Oberflächenkoordinaten anhand der lateralen Ablage der erfassten Ist-Position der Bildpunkte gegenüber der Nominal-Position der Bildpunkte der Laserlinie berechnet werden;
• • Analysieren der reduzierten Datenmenge bezüglich des Qualitätskriteriums mittels der mindestens einen Auswerteeinheit hinsichtlich dem Vorhandensein von Barcode-und/oder Textur-Information.

This object is achieved by a method for operating at least one triangulation laser scanner for identifying surface properties of a workpiece to be measured by means of the at least one triangulation laser scanner, comprising the following steps:

• Providing at least one triangulation laser scanner with a CMOS sensor chip, an imaging optic and a laser line light source for generating a laser line on the workpiece to be measured, the CMOS sensor chip and the laser line light source being arranged in a Scheimpflug condition in relation to the imaging optics;
• Providing a workpiece whose surface to be measured has at least two different regions with mutually different texture and / or at least one barcode region;
• • Detecting the surface of the workpiece to be measured by means of the at least one triangulation laser scanner by relative movement of the at least one triangulation laser scanner to the workpiece to be measured or vice versa, whereby at least a portion of the surface of the workpiece with the laser line swept over and here the lateral actual position the pixels of the laser line is detected on the CMOS sensor chip;
• • restricting the amount of data generated on the CMOS sensor chip during an image acquisition to a reduced amount of data which comprises only the data of the lateral actual position of the pixels of the laser line and the data of at least one quality criterion for each of the pixels of the detected laser line, the quality criterion being a measure for the intensity distribution along a direction transverse to the local extension direction of the pixels of the laser line on the CMOS sensor chip;
• Transferring the reduced amount of data to at least one evaluation unit at a clock rate which is greater than the maximum possible clock rate for reading out all the pixel data of the entire CMOS sensor chip;
• Generating surface coordinates of the workpiece to be measured on the basis of the detected on the CMOS sensor chip pixels of the laser line by means of the at least one evaluation, wherein the surface coordinates are calculated based on the lateral storage of the detected actual position of the pixels with respect to the nominal position of the pixels of the laser line;
• • Analyzing the reduced amount of data with respect to the quality criterion by means of the at least one evaluation unit with regard to the presence of barcode and / or texture information.

According to the invention, it has been recognized that the quality criterion contained in the reduced data quantities of a triangulation laser scanner when using a CMOS sensor chip is sufficient to ensure an analysis with regard to the presence of bar code and / or texture information. The high dynamic range of a laser scanner with CMOS sensor chip (eg by integrated HDR methods such as alternating exposure with at least 2 different exposure times, non-linear characteristic or column-wise different exposure time of the camera) leads to the fact that even with a barcode sticker with glossy surfaces and / or itself In the case of smooth texture properties of the surface, for example in the case of painted body parts, marginal differences in the reflection behavior of the surface are retained in the brightness values of the recorded sensor image or even highlighted by the nonlinearity. Moreover, according to the invention, it has additionally been recognized that the brightness differences highlighted by the non-linear response of the CMOS sensor chip are also retained retroactively in the data reduction necessary for the scanning of surfaces in the respectively applied quality criterion. In the context of the present invention, the term barcode information is not restricted to one-dimensional barcode information but, in particular, also includes two-dimensional barcode information, such as, for example, a 2D QR code.

According to the invention, in one embodiment, the at least one quality criterion is a criterion from the group: lateral Peak height, lateral peak width, ratio of lateral peak height to lateral peak width, FWHM lateral, maximum lateral gradient, number of lateral pixels above a threshold, number of lateral pixels in saturation, integral peak value in lateral direction, and convolution of the intensity distribution of detected lateral pixels the laser line on the CMOS sensor chip. The term "lateral" here means the direction transverse or perpendicular to the extension direction of the imaged laser line on the CMOS sensor chip. In a Scheimpflug triangulation laser scanner, only the laser line on the workpiece to be measured is sharply imaged, so that this "sharp" image affects only a few pixels in a lateral or perpendicular direction to the direction of extension of the image of the laser line on the CMOS sensor are. The lateral peak height is therefore defined by the maximum intensity along these few lateral pixels. Lateral peak width defines the total number of the few lateral pixels with intensity (possibly above a noise threshold). The ratio of the lateral peak height to the lateral peak width is accordingly self-explanatory. FWHM lateral means a corresponding statistical determination of the FWHM along the few lateral pixels. Maximum lateral gradient defines the maximum gradient of the lateral intensity distribution along the few lateral pixels. The number of lateral pixels in saturation or above a threshold is again self-explanatory. The integral peak value in the lateral direction hereby means the integral over the intensity distribution along the few lateral pixels. Further, the convolution of the intensity distribution of the detected lateral pixels of the laser line on the CMOS sensor chip also defines that a convolution integral of the intensity distribution along the few lateral pixels also comes into question as a measure of the intensity distribution.

By applying the mentioned quality criteria, the increased nonlinearity of the CMOS sensor chip increases the difference in the brightness values of adjacent scan points of the workpiece surface. This also applies to those criteria in which a weighting, summation or integration takes place, since these operations are carried out only in the scanning direction or along a direction transverse to the local extent direction of the pixels of the laser line on the CMOS sensor chip.

In a further embodiment of the method according to the invention, data relating to the bar and / or recognition code information and / or the texture information of the detected surface are created on the basis of the quality criterion of the reduced data quantity, which information corresponds to the information content in the bar and / or Identification code information contained information and / or the texture information of the detected surface correspond. By means of this corresponding data, the component to be measured and / or its surface areas can be identified on the basis of the information determined.

In one embodiment of the method according to the invention, the created data are visualized together with a representation of the surface coordinates of the detected surface relative to a user. This provides the user with a three-dimensional representation of the surface to be measured, for example, on a monitor or display, which also corresponds to the visual perception of the surface by the user.

In a further embodiment of the method according to the invention, after determining the presence of a bar and / or recognition code, a test plan of the workpiece corresponding to the code is selected. This has the advantage that the user is released from the correct selection of a suitable test plan for the component to be measured. The correct test plan is automatically read after determining the presence of a test plan in the at least one evaluation or semi-automatically after confirmation of the proposed test plan by the user. On the basis of the inspection plan, a quality control of the workpiece to be measured can be carried out by the evaluation unit or by the evaluation unit and the user. Thus, inexperienced persons in quality assurance can also use the method according to the invention for measuring components.

In one embodiment of the method according to the invention, the transmission of the reduced amount of data to the evaluation unit takes place wirelessly. This makes it possible to measure even a far away from the evaluation unit workpiece.

In a further embodiment, the at least one evaluation unit can process reduced amounts of data from a plurality of triangulation laser scanners in parallel. This makes it possible to measure simultaneously in a production line with multiple triangulation laser scanners a larger component such as the body of a truck or an aircraft with only one evaluation unit and there to collect the surface data.

In one embodiment of the method according to the invention, at least one outer measuring system for referencing the at least one triangulation laser scanner relative to the workpiece is present and the at least one evaluation unit adds the reduced data volumes of the at least one triangulation laser scanner and / or of several triangulation laser scanners in the correct position based on the referencing information of the external measuring system, so that with respect to the quality criterion, the assembled reduced data sets can be analyzed for the presence of barcode and / or texture information. At least one external measuring system for referencing the at least one triangulation laser scanner ensures that the data of the at least one triangulation laser scanner can be analyzed in the correct position in the global coordinate system of the at least one evaluation unit.

The object of the present invention is further achieved by a computer program product for carrying out the inventive method according to one of the aforementioned embodiments in connection with a workpiece to be measured and with a triangulation laser scanner comprising a CMOS sensor chip, an imaging optics and a laser line light source for generating a laser line on the workpiece to be measured, wherein the CMOS sensor chip and the laser line light source are arranged in relation to the imaging optics under a Scheimpflug condition, wherein the computer program product is executed on at least one control unit and at least one evaluation unit, wherein by the control unit on the CMOS sensor chip When an image is recorded, the amount of data generated is limited to a reduced amount of data and this reduced amount of data is forwarded to the at least one evaluation unit by the control unit, wherein the reduced data quantity e only those data of the lateral actual position of the pixels of the laser line and the data of at least one quality criterion for each of the pixels of the detected laser line of the triangulation laser scanner, wherein the reduced amount of data is transmitted to the evaluation unit at a clock rate which is greater than that maximum possible clock rate for reading all pixel data of the entire CMOS sensor chip of the triangulation laser scanner and wherein the evaluation unit examines the reduced amount of data of the triangulation laser scanner with respect to the quality criterion with regard to the presence of bar and / or recognition code information and / or texture information ,

In addition, the object of the present invention is achieved by a measuring system comprising an aforementioned computer program product, at least one triangulation laser scanner comprising a CMOS sensor chip, an imaging optics and a laser line light source for generating a laser line on a workpiece to be measured, wherein the CMOS sensor chip and the Laser line light source are arranged in relation to the imaging optics under a Scheimpflug condition, wherein the measuring system has at least one control unit and at least one evaluation unit, wherein the control unit limits the amount of data generated on the CMOS sensor chip during image acquisition to a reduced amount of data during operation of the measuring system, and this reduced amount of data is forwarded to the at least one evaluation unit by the control unit, wherein the reduced amount of data at least only those data of the lateral actual position of the pixels of the laser line and the data at least s of a quality criterion for each of the pixels of the detected laser line of the triangulation laser scanner, wherein the reduced amount of data is transmitted to the evaluation unit at a clock rate which is greater than the maximum possible clock rate for reading all pixel data of the entire CMOS sensor chip of the triangulation laser scanner and wherein the evaluation unit examines the reduced amount of data of the triangulation laser scanner with respect to the quality criterion with regard to the presence of bar and / or recognition code information and / or texture information.

Further features and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention with reference to the figures, the essential details of the invention show, and from the claims. The individual features can be realized individually for themselves or for several in any combination in a variant of the invention.

Embodiments of the invention will be explained in more detail with reference to FIGS. In these shows

1 a schematic representation of a triangulation laser scanner of the prior art;

2 a representation of the pixels of the CMOS sensor chip of a prior art triangulation laser scanner with Scheimpflug arrangement in the recording of a reflected from a spherical surface laser line;

3 a representation of the working range of a triangulation laser scanner of the prior art as a trapezoidal surface of the laser line level on the CMOS sensor chip and a recorded by means of the inventive method of measurement of a flat workpiece to be measured;

4 a representation of a two-dimensional projection of the obtained three-dimensional surface coordinates of a workpiece to be measured provided with gray values, which the analysis of the quality criterion according to the invention result;

5 a representation of a two-dimensional section concerning the barcode area of 4 ;

6 a representation of a measurement of different materials with mutually different texture by means of a triangulation laser scanner of the prior art using the method according to the invention;

7 a schematic representation of the data recording by means of a measuring system according to the invention; and

8th a schematic representation of the process sequence according to the invention.

1 shows a schematic representation of a triangulation laser scanner 1 of the prior art. Such a laser scanner has a laser light source 3 on whose laser light is usually fanned out by a lighting optical system in a laser plane. This laser level extends into 1 perpendicular to the paper plane, so that in 1 only a vertical line 5 This fanned laser level is located. This drawn line 5 must not with the lateral laser line on the workpiece to be measured 7 be confused, which extends laterally within the laser plane and thus perpendicular to the paper plane. The measuring range of such a triangulation laser scanner 1 now extends in the horizontal direction with respect 1 along the central area of the fanned-out laser plane of the laser light source 3 and in the vertical direction with respect to 1 between the minimum distance and the maximum distance of a workpiece to be measured 7 opposite the laser light source 3 in which a distance measurement is usefully possible.

In the distance measurement by means of such a triangulation laser scanner 1 In the prior art, this is applied to a workpiece to be measured 7 incident laser light of the laser level by means of an imaging optics 9 and a CCD or CMOS sensor chip 11 added. The incident laser light extends along a laser line within the laser plane according to the surface profile of the workpiece to be measured 7 ,

The recording of this laser line by means of the sensor chip 11 now takes place at a fixed angle between the laser light source 3 and the sensor chip 11 , so that by means of triangulation the distance of the workpiece to be measured 7 from the laser light source 3 based on the storage dx the actual position of the recorded laser line on the sensor chip 11 opposite the nominal position on the sensor chip 11 can be determined. In other words, the height difference DZ of the laser line becomes between two locations of the surface of the workpiece to be measured 7 by triangulation on the tray dx between the two picking locations of the laser line on the sensor chip 11 displayed. On the basis of this storage data of the laser line can now determine a height profile for the intersection of the laser plane with the workpiece to be measured.

By joining several such adjacent profiles, for example by scanning the workpiece 7 using the triangulation laser scanner 1 , then a 3D model of the surface of the workpiece can be 7 obtained in the form of a point cloud. For this purpose, the triangulation laser scanner 1 by hand, by means of a coordinate measuring machine or robot or otherwise relative to the workpiece to be measured 7 be moved, or vice versa.

Triangulation laser scanners of the prior art are usually constructed in compliance with the Scheimpflug condition. The Scheimpflug condition states that the image plane, the object plane, and the lens plane all intersect in one and the same line. In the case of a triangulation laser scanner, the object plane is given by the laser plane of the laser light source and the image plane by the plane of the sensor chip. The lens plane is the main plane of the lens. However, most lenses have two main levels, one object-side and one image-side. The Scheimpflug rule is therefore more precise in that the plane of sharpness with the object-side principal plane intersects at the same distance from the axis of the objective as the image plane with the image-side principal plane, and that both lines of intersection are parallel to one another. Both cut lines are located on the same side of the optical axis.

The advantage of triangulation laser scanners with Scheimpflug arrangement is that the entire laser plane of the measuring range is imaged equally sharply on the sensor chip by the imaging optics and that identical conditions are thus present throughout the entire measuring range with regard to imaging. As an alternative to a Scheimpflug arrangement, it is also possible, using free-form optics, to image several distances of a plane sharply onto a sensor chip.

Naturally, the Scheimplug arrangement also means that points of a surface to be measured, which are located outside the laser plane of the triangulation laser scanner, are no longer focused on the image due to the imaging optics Sensor chip are displayed. Thus, by means of a triangulation laser scanner with Scheimpflug arrangement, only the points within the laser plane can be detected. This is also on the 3 and the 4 as well as the corresponding description of the US 2011/267431 directed.

The 2 now shows a representation of a single shot of a laser line in a measurement of a spherical surface by means of a triangulation laser scanner of the prior art with Scheimpflug arrangement. It is based on the 2 to recognize that only the intersections of the laser plane were imaged with the spherical surface on the sensor chip in this single shot. All other points on the surface of the sphere can not be focused on the sensor chip, so they are not visible in the single image. The image of the laser line in the 2 includes in the direction of extension or extension direction of the laser line several thousand pixels or even more. Perpendicular or transverse to this direction of extension, the image of the laser line is limited to a few lateral pixels. The original of the single shot too 2 shows a black picture, in which only the recorded laser line can be seen as a bright curve. To ensure the proper publication of the 2 were the original brightness values of the original recording for the representation of 2 inverted.

The spherical surface of the workpiece to be measured 7 was in the single shot according to 2 corresponding 1 below the triangulation laser scanner 1 , Accordingly, the vertex of the laser line on the spherical surface by the amount DZ in the single shot of 2 closer to the triangulation laser scanner 1 as the edge points of the laser line. Therefore, the actual position of the apex of the laser line in the single shot is the 2 by the amount dx compared to the edge points of the laser line, see also the explanations to 1 ,

The 3 shows accordingly 2 a single shot of a laser line in the measurement of a flat sheet metal part 12 as a workpiece to be measured 7 , where the sheet metal part 12 a barcode sticker 13 which is at the single shot of the laser line for the representation of 3 was taken deliberately. The trapezoidal measuring range of the triangulation laser scanner 1 is also in the 3 located. This trapezoidal measuring range extends perpendicular to the plane of the drawing 1 along the laser line 5 , In the 3 the intensity ratios were compared to the original recording to ensure proper publication of the 3 likewise accordingly 2 inverted. The original recording of 3 shows a black trapezium with bright pixels of the laser line.

In the 3 In accordance with the invention, a quality criterion for representing the laser line on the CMOS sensor chip was used 11 applied using gray values within the measuring range. This quality criterion can be a criterion from the group: lateral peak height, lateral peak width, ratio of lateral peak height to lateral peak width, FWHM lateral, maximum lateral gradient, number of lateral pixels above a threshold, number of lateral pixels in saturation, integral peak value in lateral direction as well as a convolution of the intensity distribution of the detected lateral pixels of the laser line on the CMOS sensor chip. This in 3 Specifically applied criterion of the "lateral peak height" is in the form of the maximum lateral intensity in the lower part of the 3 applied along the laser line. Based on the here in the 3 The presence of a barcode, as opposed to the presence of a homogeneous texture of a uniform surface, can already be inferred.

It should be noted that in the case of triangulation laser scanners of the prior art, only the position data of the laser line on the sensor chip has hitherto been transmitted to an evaluation unit; 3 and the 4 as well as the corresponding description of the US 2011/267431 , To date, a quality criterion in the form of a measure of the intensity distribution has merely served to regard a measurement or a measurement point as valid or invalid. A content evaluation of a quality criterion was therefore not carried out.

The 4 shows a two-dimensional view of a sheet metal part 12 as a workpiece to be measured 7 , where the sheet metal part 12 in a flat section a barcode area 13 having. The rest of the area 14 of the bleaching part 12 is through the bare surface of the sheet metal part 12 given. The barcode area 13 of the 4 was indicated by a barcode label on the sheet metal part to be measured 12 realized, which for the purpose of testing extra on the sheet metal part 12 was attached. To this flat section with barcode area 13 shows the above discussed 3 now a single shot of a laser line measurement by means of a triangulation laser scanner with Scheimpflug arrangement.

As part of the 4 were many single shots of the bleaching part 12 corresponding 3 assembled in the correct position, so that height information for the laser line sections along the surface of the bleaching part were obtained from the X and Y positions of the pixels. This single elevation information of the single images was taken using an external referencing of the Transfer triangulation laser scanner in a global coordinate system of an evaluation. For external referencing of the tringulation laser scanner can serve here a coordinate measuring machine, the triangulation laser scanner can be attached to a so-called rotary swivel joint for arbitrary alignment in space. With the help of such a coordinate measuring machine thus the position and the pose of the triangulation laser scanner can be determined in each individual recording and transmitted to the evaluation unit for the correct position composition of the individual recordings. Likewise, robot systems are conceivable for this task. Furthermore, external referencing systems according to the 1 of the US 20110267431 used for hand-held triangulation laser scanners.

Thus, the at least one evaluation unit produces correctly assembled three-dimensional point clouds of the surface of the workpiece to be measured. In this case, a gray value corresponding to the quality criterion can be assigned to each point of these point clouds. From this, two-dimensional representations of the surface can be correspondingly 4 The reproduced gray values of the two-dimensional representation correspond to the determined gray values from the quality criterion.

The 5 now shows a two-dimensional section of the representation according to 4 concerning the barcode area 13 of the sheet metal part to be measured. From the data for the generation of 4 appropriate two-dimensional cutouts can be generated, which were identified as barcode areas. The data of these sections accordingly 5 can then be examined by means of standard software from known libraries with regard to the one- or two-dimensional barcode content. Additionally or alternatively, the data of these areas can be examined by means of speech recognition software, for example OCR, for the presence of speech information.

The 6 shows a representation of a vertical measurement of different plates of different materials to demonstrate the functionality of the inventive method with respect to the detection of different texture information. The plates made of aluminum, steel (X8), double copper with different gloss levels, black rubber (sealing material), beige plastic and dark green plastic were used for the measurement on the workpiece table of a CMM 20 filed, wherein the coordinate measuring machine 20 with a triangulation laser scanner 1 of the prior art was equipped with Scheimpflug arrangement. The surfaces of the plates were now using the triangulation laser scanner 1 scanned the prior art with Scheimpflug arrangement and it was evaluated according to the invention an associated quality criterion of the detected laser lines on the CMOS sensor chip. The quality criterion used was "number of lateral pixels in saturation plus twice the lateral peak height plus the lateral peak width". The resulting gray values of the two-dimensional representation were used to ensure proper publication of the present patent application as well as the 2 to 5 all of them as well as the 6 Based on real measurements based on the inventive method, revised by a drawing office. The 6 thus represents this revised image of the two-dimensional representation of the gray values corresponding to said quality criterion for the measurement of the different plates.

Based on 6 It can be seen that with the aid of the method according to the invention, on the one hand, surface regions of a component made of different materials, such as aluminum, steel and rubber, can be distinguished from one another. In addition, however, on the other hand, with the aid of the method according to the invention, different degrees of gloss can be distinguished in one and the same material, for example copper, or different colors of the surface areas in one and the same material, for example plastic.

The 7 shows a schematic representation of the data acquisition by means of the measuring system according to the invention 18 , This measuring system according to the invention 18 includes in the example of 7 a coordinate measuring machine 20 with a control unit 22 for controlling the coordinate measuring machine 20 and with another control unit 24 for controlling a triangulation laser scanner 1 , These control units 22 . 24 but they can also be realized in one unit. The triangulation laser scanner 1 generated for measuring a workpiece 7 a laser light plane from the in 7 only one line 5 is located, see also the figure description of 1 , The coordinate measuring machine 20 serves with its control unit 22 in addition, the triangulation laser scanner 1 in the correct position relative to the workpiece to be measured 7 to position and align. The control unit 22 guides machine data 26 to an evaluation unit 30 further. This machine data 26 include the position and orientation data of the triangulation laser scanner 1 within the coordinate system of the coordinate measuring machine 20 , The further control unit 24 of the coordinate measuring machine 20 on the one hand ensures control of the triangulation laser scanner 1 in itself and on the other hand for a reduction in the sensor chip 11 of the triangulation laser scanner 1 accumulating data on only those data of the lateral actual position of the pixels of the laser line and the data of at least one quality criterion for each of the pixels of the detected laser line. This reduced amount of data 28 is the part of the other control unit 24 also to the at least one evaluation unit 30 forwarded. The evaluation unit 30 generates the surface coordinates of the workpiece to be measured using the CMOS sensor chip 11 captured pixels of the laser line, wherein the surface coordinates are calculated on the basis of the lateral storage of the detected actual position of the pixels with respect to the nominal position of the pixels of the laser line. Here are the data of the triangulation laser scanner 1 due to the machine data 26 of the coordinate measuring machine 20 position and position joined together.

The triangulation laser scanner 1 of the 7 of the coordinate measuring machine 20 served to accommodate the in the 2 to 6 displayed data and has a CMOS sensor chip 11 , an imaging optics 9 and a laser line light source 3 for generating a laser line on a workpiece to be measured 7 on, with the CMOS sensor chip 11 and the laser line light source 3 in relation to the imaging optics 9 are arranged under a Scheimpflug condition.

• • Bereitstellen mindestens eines Triangulations-Laserscanners 1 mit einem CMOS Sensorchip 11, einer Abbildungsoptik 9 und einer Laserlinien-Lichtquelle 3 zur Erzeugung einer Laserlinie auf dem zu vermessenden Werkstück 7, wobei der CMOS Sensorchip 11 und die Laserlinien-Lichtquelle 3 in Relation zur Abbildungsoptik 9 unter einer Scheimpflug-Bedingung angeordnet sind;
• • Bereitstellen eines Werkstücks 7, dessen zu vermessende Oberfläche mindestens zwei verschiedene Bereiche 13, 14; 15 mit zueinander unterschiedlicher Textur 15 und/oder mindestens einen Bar- und/oder Erkennungs-Code-Bereich 13 aufweist;
• • Erfassen der Oberfläche 42 des zu vermessenden Werkstücks 7 mittels des mindestens einen Triangulations-Laserscanners 1 durch Relativbewegung des mindestens einen Triangulations-Laserscanners 1 zu dem zu vermessenden Werkstück 7, wodurch wenigstens ein Teil der Oberfläche des Werkstücks 7 mit der Laserlinie überstrichen und hierbei die laterale Ist-Position der Bildpunkte der Laserlinie auf dem CMOS Sensorchip 11 erfasst wird;
• • Beschränken 44; 46 der auf dem CMOS Sensorchip 11 bei einer Bildaufnahme erzeugten Datenmenge auf eine reduzierte Datenmenge 28, welche lediglich die Daten der lateralen Ist-Position der Bildpunkte der Laserlinie (Beschränkungsschritt 44 des Verfahrens) und die Daten mindestens eines Qualitätskriteriums (Beschränkungsschritt 46 des Verfahrens) für jeden der Bildpunkte der erfassten Laserlinie umfasst, wobei das Qualitätskriterium ein Maß für die Intensitätsverteilung entlang einer Richtung quer zur lokalen Erstreckungsrichtung der Bildpunkte der Laserlinie auf dem CMOS Sensorchip 11 ist;
• • Übertragen 48 der reduzierten Datenmenge 28 an eine Auswerteeinheit 30 mit einer Taktrate, welche größer ist als die maximal mögliche Taktrate zur Auslesung aller Pixeldaten des gesamten CMOS Sensorchips 11;
• • Erzeugen von Oberflächenkoordinaten 50 des zu vermessenden Werkstücks 7 anhand der auf dem CMOS Sensorchip 11 erfassten Bildpunkte der Laserlinie mittels der Auswerteeinheit 30, wobei die Oberflächenkoordinaten anhand der lateralen Ablage der erfassten Ist-Position der Bildpunkte gegenüber der Nominal-Position der Bildpunkte der Laserlinie berechnet werden;
• • Analysieren 52 der reduzierten Datenmenge 28 bezüglich des Qualitätskriteriums mittels der Auswerteeinheit 30 hinsichtlich dem Vorhandensein von Bar- und/ oder Erkennungs-Code-Information 13 und/oder Textur-Information 15.

The 8th schematically shows a method according to the invention 40 to operate at least one triangulation laser scanner 1 for identifying surface properties of a by means of the at least one triangulation laser scanner 1 to be measured workpiece 7 comprising the following steps:

• • Provide at least one triangulation laser scanner 1 with a CMOS sensor chip 11 , an imaging optics 9 and a laser line light source 3 for generating a laser line on the workpiece to be measured 7 , where the CMOS sensor chip 11 and the laser line light source 3 in relation to the imaging optics 9 are arranged under a Scheimpflug condition;
• • Provision of a workpiece 7 whose surface to be measured at least two different areas 13 . 14 ; 15 with mutually different texture 15 and / or at least one bar and / or recognition code area 13 having;
• • Capture the surface 42 of the workpiece to be measured 7 by means of the at least one triangulation laser scanner 1 by relative movement of the at least one triangulation laser scanner 1 to the workpiece to be measured 7 , whereby at least part of the surface of the workpiece 7 with the laser line and thereby the lateral actual position of the pixels of the laser line on the CMOS sensor chip 11 is recorded;
• • Restrict 44 ; 46 the one on the CMOS sensor chip 11 in an image acquisition generated amount of data to a reduced amount of data 28 , which only the data of the lateral actual position of the pixels of the laser line (restriction step 44 of the method) and the data of at least one quality criterion (restriction step 46 of the method) for each of the pixels of the detected laser line, the quality criterion being a measure of the intensity distribution along a direction transverse to the local extent direction of the pixels of the laser line on the CMOS sensor chip 11 is;
• • Transfer 48 the reduced amount of data 28 to an evaluation unit 30 at a clock rate which is greater than the maximum possible clock rate for reading all pixel data of the entire CMOS sensor chip 11 ;
• • Create surface coordinates 50 of the workpiece to be measured 7 based on the on the CMOS sensor chip 11 captured pixels of the laser line by means of the evaluation unit 30 wherein the surface coordinates are calculated from the lateral storage of the detected actual position of the pixels with respect to the nominal position of the pixels of the laser line;
• • Analyze 52 the reduced amount of data 28 with regard to the quality criterion by means of the evaluation unit 30 for the presence of bar and / or recognition code information 13 and / or texture information 15 ,

Here, one criterion from the group: lateral peak height, lateral peak width, ratio of the lateral peak height to the lateral peak width, lateral FWHM, maximum lateral gradient, number of lateral pixels above a threshold, number of lateral pixels in saturation, integral peak value in the lateral direction and a convolution of the intensity distribution of the detected lateral pixels of the laser line can be selected on the CMOS sensor chip. It is important here that the quality criterion forms a measure of the intensity distribution along a direction transverse to the local direction of extent of the pixels of the laser line on the CMOS sensor chip, which determines the brightness differences in the intensity values during formation due to the non-linear brightness sensitivity of the CMOS sensor chip of the quality criterion.

In the method according to the invention 40 can use the quality criterion of the reduced amount of data data regarding the bar and / or recognition code information 13 and / or the texture information 15 the recorded surface, which corresponds to the information contained in the bar and / or recognition code information 13 contained information and / or the texture information 15 correspond to the detected surface. This corresponding data can be used to identify the component to be measured and / or its surface areas on the basis of the information found. The 5 and 6 represent corresponding data regarding bar and / or recognition code information 13 and / or the texture information 15 the detected surface.

In another step 54 the method according to the invention 40 The generated data can be visualized to a user together with a representation of the surface coordinates of the detected surface. For this purpose, the data created must first be linked with the data of the acquired surface coordinates in the correct position and position. Subsequently, this data can then be output, for example, on a monitor together with the surface coordinates. This is on 4 referenced, there are both surface coordinates and bar and / or recognition code information 13 reproduced in a representation.

In one embodiment of the method according to the invention 40 may upon detection of the presence of bar and / or recognition code information 13 in step 52 of the method a test plan corresponding to the code of the workpiece 7 to be selected. This makes it possible, for example, to visualize inspection features of the workpiece to be measured simultaneously with the data of step 54 with respect to the user.

The transmission of the reduced amount of data in the step 48 the method according to the invention 40 to the at least one evaluation unit 30 can be wireless In addition, the at least one evaluation unit 30 reduced data volumes of several triangulation laser scanners 1 process in parallel.

Furthermore, at least one outer measuring system, for example the coordinate measuring machine 20 of the 7 , for referencing the at least one triangulation laser scanner 1 be provided relative to the workpiece, wherein the at least one evaluation unit 30 the reduced data volumes of the at least one triangulation laser scanner 1 and / or multiple triangulation laser scanners 1 assembled in the correct position according to the referencing information of the external measuring system, so that with regard to the quality criterion the assembled reduced data sets with regard to the presence of bar and / or recognition code information 13 and / or texture information 15 can be analyzed. With the help of such a coordinate measuring machine 20 of the 7 as an external measuring system, for example, the assembled reduced data volumes of the 4 respectively. 5 be won. In addition, however, it may be in the detection of surface coordinates of large workpieces such as aircraft fuselages or wings in step 42 the method according to the invention 40 by means of several independent triangulation laser scanners 1 also occur that only a portion of a bar and / or recognition code information 13 and / or texture information 15 from a triangulation laser scanner 1 is detected and the other sub-areas or the remaining sub-area by another triangulation laser scanner 1 be recorded. In this case, it is then necessary for at least one external measuring system to interact with at least one evaluation unit 30 ensures the merging of the acquired data in a common coordinate system and that the at least one evaluation unit 30 the merged data relating to the quality criterion for the presence of bar and / or recognition code information 13 and / or texture information 15 in step 52 the method according to the invention 40 examined.

In addition, the present invention comprises a computer program product for carrying out the method according to the invention 40 according to 8th on at least one control or evaluation unit 30 in connection with a triangulation laser scanner 1 according to 7 having a CMOS sensor chip 11 , an imaging optics 9 and a laser line light source 3 for generating a laser line on a workpiece to be measured 7 , where the CMOS sensor chip 11 and the laser line light source 3 in relation to the imaging optics 9 are arranged under a Scheimpflug condition.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 6260001 B1 [0003]
• US 8284240 B2 [0004]
• US 2011/267431 [0035, 0040]
• US 20110267431 [0042]

Claims (10)

Procedure ( 40 ) for operating at least one triangulation laser scanner ( 1 ) for identifying surface properties of a by means of the at least one triangulation laser scanner ( 1 ) to be measured workpiece ( 7 ) comprising the following steps: • providing at least one triangulation laser scanner ( 1 ) with a CMOS sensor chip ( 11 ), an imaging optics ( 9 ) and a laser line light source ( 3 ) for generating a laser line on the workpiece to be measured ( 7 ), where the CMOS sensor chip ( 11 ) and the laser line light source ( 3 ) in relation to the imaging optics ( 9 ) are arranged under a Scheimpflug condition; • Provision of a workpiece ( 7 ) whose surface to be measured has at least two different regions ( 13 . 14 ; 15 ) with mutually different texture ( 15 ) and / or at least one bar and / or recognition code area ( 13 ) having; • Capture the surface ( 42 ) of the workpiece to be measured ( 7 ) by means of the at least one triangulation laser scanner ( 1 ) by relative movement of the at least one triangulation laser scanner ( 1 ) to the workpiece to be measured ( 7 ), whereby at least part of the surface of the workpiece ( 7 ) with the laser line and thereby the lateral actual position of the pixels of the laser line on the CMOS sensor chip ( 11 ) is detected; • Restrict ( 44 ; 46 ) on the CMOS sensor chip ( 11 ) in an image acquisition generated data amount to a reduced amount of data ( 28 ), which comprises only the data of the lateral actual position of the pixels of the laser line and the data of at least one quality criterion for each of the pixels of the detected laser line, the quality criterion being a measure of the intensity distribution along a direction transverse to the local extension direction of the pixels of the laser line the CMOS sensor chip ( 11 ); • Transfer ( 48 ) the reduced amount of data ( 28 ) to at least one evaluation unit ( 30 ) at a clock rate which is greater than the maximum possible clock rate for reading all the pixel data of the entire CMOS sensor chip ( 11 ); • generation of surface coordinates ( 50 ) of the workpiece to be measured ( 7 ) based on the CMOS sensor chip ( 11 ) captured pixels of the laser line by means of the at least one evaluation unit ( 30 ), wherein the surface coordinates are calculated from the lateral storage of the detected actual position of the pixels with respect to the nominal position of the pixels of the laser line; • Analyze ( 52 ) the reduced amount of data ( 28 ) with regard to the quality criterion by means of the at least one evaluation unit ( 30 ) regarding the presence of bar and / or recognition code information ( 13 ) and / or texture information ( 15 ). Procedure ( 40 ) according to claim 1, wherein the at least one quality criterion is a criterion from the group: lateral peak height, lateral peak width, ratio of lateral peak height to lateral peak width, FWHM lateral, maximum lateral gradient, number of lateral pixels above a threshold, number of lateral Pixels in saturation, integral peak value in the lateral direction and a convolution of the intensity distribution of the detected lateral pixels of the laser line on the CMOS sensor chip ( 11 ). Procedure ( 40 ) according to one of the preceding claims, wherein based on the quality criterion the reduced amount of data ( 28 ) Data regarding the bar and / or recognition code information ( 13 ) and / or the texture information ( 15 ) of the detected surface, which correspond to the information content of the information contained in the bar and / or recognition code information ( 13 ) and / or texture information ( 15 ) correspond to the detected surface. Procedure ( 40 ) according to claim 3, wherein in a further step ( 54 ) the generated data are visualized together with a representation of the surface coordinates of the detected surface to a user. Procedure ( 40 ) according to any one of the preceding claims, wherein upon detection of the presence of bar and / or recognition code information ( 13 ) a test plan of the workpiece corresponding to the code ( 7 ) is selected. Procedure ( 40 ) according to one of the preceding claims, wherein the transmission ( 48 ) the reduced amount of data ( 28 ) to the at least one evaluation unit ( 30 ) takes place wirelessly. Procedure ( 40 ) according to one of the preceding claims, wherein the at least one evaluation unit ( 30 ) reduced data volumes ( 28 ) of several triangulation laser scanners ( 1 ) can process in parallel. Procedure ( 40 ) according to one of the preceding claims, wherein at least one outer measuring system ( 20 ) for referencing the at least one triangulation laser scanner relative to the workpiece ( 7 ) and the at least one evaluation unit ( 30 ) the reduced data volumes ( 28 ) of the at least one triangulation laser scanner ( 1 ) can be assembled in the correct position on the basis of the referencing information, so that, with regard to the quality criterion, the combined reduced data volumes in terms of the presence of bar and / or recognition code information ( 13 ) and / or texture information ( 15 ) can be analyzed. Computer program product for carrying out one of the methods ( 40 ) according to one of the preceding claims in connection with a workpiece to be measured ( 7 ) and with a triangulation laser scanner ( 1 ) comprising a CMOS sensor chip ( 11 ), an imaging optics ( 9 ) and a laser line light source ( 3 ) for generating a laser line on the workpiece to be measured ( 7 ), where the CMOS sensor chip ( 11 ) and the laser line light source ( 3 ) in relation to the imaging optics ( 9 ) are arranged under a Scheimpflug condition, wherein the computer program product on at least one control unit ( 22 ; 24 ) and at least one evaluation unit ( 30 ) is carried out, wherein by the control unit ( 22 ; 24 ) on the CMOS sensor chip ( 11 ) in an image acquisition generated data amount to a reduced amount of data ( 28 ) and this reduced amount of data ( 28 ) to the at least one evaluation unit ( 30 ) by the control unit ( 22 ; 24 ), the reduced amount of data ( 28 ) only those data of the lateral actual position of the pixels of the laser line and the data of at least one quality criterion for each of the pixels of the detected laser line of the triangulation laser scanner ( 1 ), where the reduced amount of data ( 28 ) to the evaluation unit ( 30 ) is transmitted at a clock rate which is greater than the maximum possible clock rate for reading all the pixel data of the entire CMOS sensor chip ( 11 ) of the triangulation laser scanner ( 1 ) and wherein the evaluation unit ( 30 ) the reduced amount of data ( 28 ) of the triangulation laser scanner ( 1 ) with regard to the quality criterion with regard to the presence of bar and / or recognition code information ( 13 ) and / or texture information ( 15 ). Measuring system ( 18 ) comprising a computer program product according to claim 9, at least one triangulation laser scanner ( 1 ) comprising a CMOS sensor chip ( 11 ), an imaging optics ( 9 ) and a laser line light source ( 3 ) for producing a laser line on a workpiece to be measured ( 7 ), where the CMOS sensor chip ( 11 ) and the laser line light source ( 3 ) in relation to the imaging optics ( 9 ) are arranged under a Scheimpflug condition, the measuring system ( 18 ) at least one control unit ( 22 ; 24 ) and at least one evaluation unit ( 30 ), wherein during operation of the measuring system ( 18 ) the control unit ( 22 ; 24 ) on the CMOS sensor chip ( 11 ) in an image acquisition generated data amount to a reduced amount of data ( 28 ) and this reduced amount of data ( 28 ) to the at least one evaluation unit ( 30 ) by the control unit ( 22 ; 24 ), the reduced amount of data ( 28 ) only those data of the lateral actual position of the pixels of the laser line and the data of at least one quality criterion for each of the pixels of the detected laser line of the triangulation laser scanner ( 1 ), where the reduced amount of data ( 28 ) to the evaluation unit ( 30 ) is transmitted at a clock rate which is greater than the maximum possible clock rate for reading all the pixel data of the entire CMOS sensor chip ( 11 ) of the triangulation laser scanner ( 1 ) and wherein the evaluation unit ( 30 ) the reduced amount of data ( 28 ) of the triangulation laser scanner ( 1 ) with regard to the quality criterion with regard to the presence of bar and / or recognition code information ( 13 ) and / or texture information ( 15 ).

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